There is no one view of the moods in Ancient Greek. But
there is general consensus over several aspects, and this consensus
fits in well with modern views on modal systems generally. According
to this general consensus, the optative is more remote than the subjunctive,
which is more remote than the indicative, which may be represented by
an irrealis
continuum.

The meanings of the moods were traditionally divided into
two: those with an element of will (hortative, negative directive, wish),
and those without (future, potential). This fits well with the division,
seen as fundamental in many studies of modality, between deontic
and epistemic modality.

However, there are problems with these traditional views.
Findings from the theory of grammaticalisation suggest that the table
is too rigid, and modality studies suggest that the table is too simplistic.
Furthermore, the 'deontic' meanings are not deontic but performative,
or 'speaker-oriented'.